Laboratory Door Signs:

The Boston Fire Department regulations require the National Fire Protection Association (NFPA) 704 Diamond to be posted on all laboratory doors. This sign shall be accurate and identify all hazards located in the laboratory.

NFPA Hazard Rating System

Northeastern University’s laboratory doors are posted with emergency information to warn occupants and The Boston Fire Department personnel of the presence and identification of hazardous materials inside each laboratory. The National Fire Protection Association (NFPA) has developed a system for indicating the health, flammability, reactivity and special hazards for many common chemicals through use of the NFPA 704 Diamond. The hazard rating for the laboratory is determined by looking at all the chemicals, gases and special lab uses in the laboratory and coming up with a rating for each hazard category based on criteria established below.

Please read the rating information in each category, take an inventory of your laboratory and rate each category accordingly. To look up a rating for a particular chemical click on the link at the bottom of the page. If you do not find the chemical listed, a review of the chemicals safety data sheet (SDS) may help you rate the chemical in question.

Keeping Signs Current

Every effort shall be made to keep the information on the 704 diamonds current. The laboratory Principal Investigator (PI) or Group Compliance Liaison shall review his/her hazardous materials and equipment inventory and update the correct data for each room attached to your laboratory profile. EH&S will review the request and change the door sign accordingly.

How to Request Change

Please submit any changes on your laboratory profile on BioRAFT. If you have any questions on how to submit these changes please refer to the following link to the fact sheet, click here. Once you have submitted these changes, a member of EH&S will review and deliver the new sign.

Request Laboratory Door Sign holder

If you need a laboratory door sign holder, log in to myNEU and click on Services and Links to access the Facilities Online Work Request to submit a request to the Sign Shop.


If there are any questions regarding a chemical rating, please either email your question or call the Office of Environmental Health and Safety at 617-373-2769.

If you have a new laboratory or are a new Principal Investigator, please contact Office of Environmental Health and Safety or call 617-373-2769

Rating Summary


Use the most severe rating code regardless of volume.

Health (Blue) Detailed Description of Health Rating

4 Danger May be fatal on short exposure. Specialized protective equipment required
3 Warning Corrosive or toxic. Avoid skin contact or inhalation
2 Warning May be harmful if inhaled or absorbed
1 Caution May be irritating
0 No unusual hazard

The greatest volume of one code determines the marking. The only exception is if a more severe code has a volume of 3 gallons or greater, then that code is used instead of a lower code of greater volume. If the laboratory total volume of flammables or combustibles is less than one pint for all, then the rating for the laboratory for this area shall be zero

Flammability (Red) Detailed Description of Flammable Rating

4 Danger Flammable gas or extremely flammable liquid
3 Warning Flammable liquid flash point below 100°F
2 Caution Combustible liquid flash point of 100° to 200°F
1 Combustible if heated
0 Not combustible

Use the most severe rating code regardless of volume.

Reactivity (Yellow) Detailed Description of Reactivity Rating

4 Danger Explosive material at room temperature
3 Danger May be explosive if shocked, heated under confinement or mixed with water
2 Warning Unstable or may react violently if mixed with water
1 Caution May react if heated or mixed with water but not violently
0 Stable Not reactive when mixed with water

Special Information

Special Information Key (White)

Detailed Description of Special Information Rating

Indicate the presence of the following regardless of volume.

Oxy Oxidizing Agent
W Water Reactive
G Compressed Gas
LN2 Liquid Nitrogen
LHE Liquid Helium
Special Signage Key (These are signs that shall or must be posted in addition to the NFPA diamond)
LAS Laser
BL Biosafety Level
RAD Radioactive Material
X-Ray X-Ray Diffractometer
MAG Magnetic Fields
HVO High Voltage

NFPA Hazard Rating A – C

NFPA Hazard Rating D – I

NFPA Hazard Rating J – R

NFPA Hazard Rating S – Z

NFPA Rating Gases